Relay



., ET AL 2,8903 1 0 INVENTOR.

WILLIAM L..CARLSON, JR. WILLIAM J. ROBINSON 9 4 1Q ATTORNEY 4 .l .I Y B n 2 M m 5 m a r 2. 3 q Twc u w a m N "I 4 v E fi r zzz u w 4 a 1 w W June 9, 1959 United States Patent M RELAY William L. Carlson, Jr., Bloomington, and William J.

Robinson, Richfield, Minn., assignors to Minneapolis- Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Application August 5, 1957, Serial No. 676,275

8 Claims. (Cl. 200112) The present invention is directed to a relay and more specifically to a relay utilizing a conductive fluid for its operating means.

While the basic principles utilized in the present novel device have been known for many years their application to a device of the type disclosed has not been made. The present device uses the principle that a conductive ring which is cut by an alternating current magnetic field has a current induced therein. The current reacts with the cutting flux and produces a force on the conductive ring perpendicular to the flux. This force then moves the conductive ring if no restraining force is provided. The present principle has been utilized to manufacture toy devices which fire conductive metallic rings from a post when a magnetic field is properly placed across the ring and the principle has been also used in the production of certain types of a liquid metal and conductive fluid pumps. These pumps are sometimes referred to as Faraday type pumps or electromagnetic induction type pumps.

It is an object of the present invention to utilize the electromagnetic conductive fluid pump principles to provide a relay in which the sole moving part is a conductive fluid such as a liquid metal.

It is a further object of the present invention to disclose a novel relay which has no binding parts and which is silent in operation.

It is still a further object of the present invention to disclose a relay which is hermetically sealed and is capa ble of handling substantial current loads.

Yet another object of the present invention is to disclose a relay which is rugged and simple in construction.

These and other objects will become apparent when the single sheet of drawings is considered wherein:

Figure 1 is a cross section of the relay in a vertical plane, and;

Figure 2 is a cross section of the relay in a horizontal plane along 2-2, showing the toroidal construction of the device.

A toroidal coil 10 has energizing leads 11 and 12. This coil is substantially completely encased in a magnetic housing generally shown as 14. The housing 14 has a bottom member 15, a side member 16, a top member 17 and an annular central member 18. The annular central member 18 is kept a substantial distance above the bottom member so as to maintain a large magnetic air gap. Any magnetic flux in the housing 14 will pass from the annular central member 18 to a magnetic core 20 which is substantially on the axis of the coil 10. Whenever the coil 10 is energized by connecting leads 11 and 12 to an alternating current source of power, a magnetic flux flows around the housing 14 and passes across the gap created between the annular member 18 and core 20, as opposed to crossing the larger air gap between the annular member 18 and the bottom member 15.

A container 25, which is disclosed as made of a nonmagnetic material such as glass, is formed having an annular lower section 26 and a generally cylindrical upper section 27. It is understood that the container could to 2,890,310 Patented June 9, 1959 be formed as an integral part of the housing 14. The annular section 26 is inserted in the gap between the annular member 18 of the housing 14 and the core 20. When the container 25 is so inserted there remains the cylindrical section 27 above the core 20 and the housing 14. The container 25 has two electrodes 30 and 31 hermetically sealed and insulated therein at 32 and 33. The electrodes 30 and 31 have appropriate lead wires 34 and 35 attached thereto, and these lead wires are utilized in any convenient relay circuit (not shown).

The interior of container 25 is partially filled with a conductive fluid 40. This conductive fluid may be of any convenient type but is preferably a liquid metal such as mercury, sodium, potassium, or a sodium-potassium mixture. It will be understood that both mercury and a sodium-potassium mixture are normally fluids at normal ambient temperatures, while sodium and potassium alone could be utilized for high temperature applications. The preferred embodiment of the present device utilizes the sodium-potassium mixture as it is liquid to approximately 12 F. If it is desired to use the present relay in low temperature applications the conductive fluid 40 would be mercury or a mercury compound.

In addition to the conductive fluid 40 contained in the container 25, a space 41 is left between the conductive fluid and the electrodes 30 and 31. The space 41 is preferably evacuated, but in some applications this space could contain inert gases, or when the device is used with such liquid metals as mercury the space 41 could be vented to the atmosphere.

Operation In the present application, the device shown in Figure l is in a (lo-energized position. In the de-energized position the conductive fluid 40 does not make contact between the electrodes 30 and 31 thereby leaving an open circuit between the conductors 34 and 35. If it is desired to complete a circuit through the wires 34 and 35 an alternating current potential is applied to conductors 11 and 12. The energization of coil 10 by applying the alternating current potential creates a magnetic flux in the housing 14 which passes between the annular member 18 and the core 20. This alternating current flux cuts across an annular ring of a conductive fluid contained in the portion 26 of the container 25. It is well known that an alternating current flux cutting a ring of conductive material induces a current therein. A current is induced in the conductive fluid 40 in the annular section 26 and flows around in an annular path thereby ringing the core 20 with a flow of current. The current flowing in the annular path then reacts with the flux which creates it to pump or move the conductive fluid 40 mutually perpendicular to both the current and flux. In the present case that direction would be in the upward direction and the conductive fluid 40 will then tend to move upward in the container 25. The fluid 40 continues to move upwardly in the container 25 until the conductive fluid 40 short circuits the electrodes 30 and 31. The short circuiting of electrodes 30 and 31 completes the external circuit through the conductors 34 and 35 and thereby provides a relay having unique properties.

The presently disclosed relay could be modified structurally in many ways within the scope of the applicants teaching by those versed in the art. Since many modifications are possible in the present device the applicants wish to be limited in their invention only to the scope of the appended claims.

We claim as our invention:

1. A relay of the class described: a single phase toroidal energizing winding; a magnetic case partially enclosing said winding; said case having a magnetic core on the axis of the winding and forming an annular air gap with said case; a container in said annular air gap and extending above said core; current control. means inserted into said container; and a conductive fluid partially filling said container; said fluid rising in said container under the influence of a stationary magnetic field of said Winding and a resultant annular induced current upon the energization of said Winding; said rising fluid operating said current control means.

2. A relay of the class described: a single phase toroidal energizing Winding; a magnetic case partially enclosing said Winding; said case having a magnetic core on the axis of the winding and forming an annular air gap with said case; a nonmagnetic container in said annular air gap and extending above said core; current control means inserted into said container; and a liquid metal partially filling said container, said liquid metal rising in said container under the influence of a stationary magnetic field of said Winding and a resultant annular induced current upon the energization of said Winding; said rising liquid metal operating said current control means.

3. A relay of the class described: a single phase toroidal energizing winding; a magnetic case partially enclosing said winding; said case having a cylindrical magnetic core on the axis of the Winding and forming an annular air gap With said case; a nonmagnetic container in said annular air gap and extending above said core; electrodes inserted into said container; and a liquid metal partially filling said container; said liquid metal rising in said container under the influence of a stationary magnetic field of said winding and a resultant annular induced current upon the energization of said Winding; said rising liquid metal electrically shorting said electrodes.

4. A relay of the class described: a single phase toroidal energizing winding; a magnetic case partially enclosing said Winding; said case having a cylindrical magnetic core on the axis of the winding and forming an annular air gap with said case; a nonmagnetic container in said annular air gap and extending above said core; a pair of electrodes inserted into the top of said container; and a liquid metal partially filling said container; said liquid metal rising in said container under the influence of a stationary magnetic field of said Winding and a resultant annular induced current upon the energization .4 of said winding; said rising liquid metal electrically short circuiting said pair of electrodes.

5. A device of the class described: energizing means including means for controllably creating a stationary toroidal magnetic field; container means having an annular portion disposed in said field; said container partially filled with a conductive fluid; and current control means in said container and operated by the rise of said fluid; said fluid rising in said container under the influence of said magnetic field and a resultant annular induced current upon the existence of said field.

6. A relay of the class described: single phase energizing means including means for controllably creating a stationary toroidal magnetic field; nonmagnetic container means having an annular portion disposed centrally in said field; said container partially filled With a liquid metal; and current control means in said container and operated by the rise of said liquid metal; said liquid metal rising in said container under the influence of said magnetic field and a resultant annular induced current upon the existence of said field.

7. A relay of the class described: single phase energizing means including means for controllably creating a stationary toroidal magnetic field; container means having an annular portion disposed centrally in said field; said container partially filled with a liquid metal; and electrodes in said container and short circuited by the rise of said liquid metal; said liquid metal rising in said container under the influence of said magnetic field and a resultant annular induced current upon the existence of said field.

8. A relay of the class described: single phase energizing means including toroidal core means having an air gap for controllably creating a stationary toroidal magnetic field; container means having an annular portion disposed centrally in said field; said container partially filled with a liquid metal; and electrodes in said container and short circuited by the rise of said liquid metal; said liquid metal rising in said container under the infiuence of said magnetic field and a resultant annular in duced current upon the existence of said field.

References Cited in the file of this patent UNITED STATES PATENTS 983,245 Lohr Jan. 31, 1911 

